As authorities continue to investigate anthrax attacks, some are questioning what, if anything, might be targeted next. Experts say one possibility is the Internet.

There are many ways terrorists could use computers and the Internet to cause harm, said Kathleen Kimball, director of Penn State's Computer and Network Security Office.

One method is to make networks inaccessible with a denial of service attack, Kimball said.

A denial of service attack is "essentially flooding a system" with electronic traffic, Kimball said.

"It's a malicious code that breaks into a system, then a code is implanted and told to flood whatever they want," she said.

Denial of service attacks prevent legitimate use of computer resources by attacking a system connected to the Internet, according to the CERT Coordination Center's Web site (www.cert.org), an Internet security center.

The problems caused by denial of service attacks can be fixed in varying amounts of time, Kimball said.

"It depends on the nature that they would attack," she said.

Initial denial of service attacks involves a single source attacking a single target, according to the CERT Coordination Web site. Now there are tools to attack multiple targets from multiple sources, the Web site said.

Viruses are another means of attacking communication through computers and also self-replicate, Kimball said.

Chris Snyder, project manager at Lazerpro Digital Media Group, 220 Regent Court, said viruses could easily be used by terrorists to cause multiple problems.

"Each virus acts differently. They really could attack anything from a hard drive to freezing a computer to mass e-mailing itself," Snyder said.

It would be possible for terrorists to attack a server, but they probably would need direct access to it, Snyder added.

"I don't think it's likely," he said. "Most security should prevent a large-scale attack."

Snyder said these types of computer attacks would not be very effective for terrorists.

A hacker recently attacked Lazerpro Digital Media Group's system and the person was caught within 15 minutes, Snyder said.

"Everyone's keeping their eyes open," he added.

Most students are not concerned that terrorists will cause any communication problems with computers.

"I think the most likely attack would be a virus, but I'm not too worried," said Elias Grim (junior-management science and information systems).

Kimball said Penn State would probably not be affected by any potential terrorist Internet attacks.

"Penn State is not as likely a target as going after an insecure system," she said.

The university has taken many steps to create a safe computer system but has not taken any extra precautions against terrorist attacks to the system.

"We're always concerned about safety," Kimball said. The Computer and Network Security Office educates colleges and departments about computer safety by teaching multiple classes.

Generally, Kimball said people should not worry about the possibility of terrorist computer and Internet attacks.

"The Internet can be used for good and for ill. I don't want to panic people," she said.